A385404 - cp's OEIS frontend

A385404 Numbers that can be split into two at any place between their digits such that the resulting numbers are always a nonprime on the left and a prime on the right.

n	a(n)
1	12
2	13
3	15
4	17
5	42
6	43
7	45
8	47
9	62
10	63
11	65
12	67
13	82
14	83
15	85
16	87
17	92
18	93
19	95
20	97
21	123
22	143
23	147
24	153
25	167
26	183
27	423
28	443
29	447
30	453
31	467
32	483
33	497
34	623
35	637
36	643
37	647
38	653
39	667
40	683
41	697
42	813
43	817
44	823
45	843
46	847
47	853
48	867
49	873
50	883
51	913
52	917
53	923
54	937
55	943
56	947
57	953
58	967
59	983
60	997

[12, 13, 15, 17, 42, 43, 45, 47, 62, 63, 65, 67, 82, 83, 85, 87, 92, 93, 95, 97, 123, 143, 147, 153, 167, 183, 423, 443, 447, 453, 467, 483, 497, 623, 637, 643, 647, 653, 667, 683, 697, 813, 817, 823, 843, 847, 853, 867, 873, 883, 913, 917, 923, 937, 943, 947, 953, 967, 983, 997]

cp's OEIS Frontend

A385404 Numbers that can be split into two at any place between their digits such that the resulting numbers are always a nonprime on the left and a prime on the right.

Table of values

List of values

n	a(n)
1	12
2	13
3	15
4	17
5	42
6	43
7	45
8	47
9	62
10	63
11	65
12	67
13	82
14	83
15	85
16	87
17	92
18	93
19	95
20	97
21	123
22	143
23	147
24	153
25	167
26	183
27	423
28	443
29	447
30	453
31	467
32	483
33	497
34	623
35	637
36	643
37	647
38	653
39	667
40	683
41	697
42	813
43	817
44	823
45	843
46	847
47	853
48	867
49	873
50	883
51	913
52	917
53	923
54	937
55	943
56	947
57	953
58	967
59	983
60	997

n	a(n)
1	12
2	13
3	15
4	17
5	42
6	43
7	45
8	47
9	62
10	63
11	65
12	67
13	82
14	83
15	85
16	87
17	92
18	93
19	95
20	97
21	123
22	143
23	147
24	153
25	167
26	183
27	423
28	443
29	447
30	453
31	467
32	483
33	497
34	623
35	637
36	643
37	647
38	653
39	667
40	683
41	697
42	813
43	817
44	823
45	843
46	847
47	853
48	867
49	873
50	883
51	913
52	917
53	923
54	937
55	943
56	947
57	953
58	967
59	983
60	997

n	a(n)
1	12
2	13
3	15
4	17
5	42
6	43
7	45
8	47
9	62
10	63
11	65
12	67
13	82
14	83
15	85
16	87
17	92
18	93
19	95
20	97
21	123
22	143
23	147
24	153
25	167
26	183
27	423
28	443
29	447
30	453
31	467
32	483
33	497
34	623
35	637
36	643
37	647
38	653
39	667
40	683
41	697
42	813
43	817
44	823
45	843
46	847
47	853
48	867
49	873
50	883
51	913
52	917
53	923
54	937
55	943
56	947
57	953
58	967
59	983
60	997